The ink is too light or smears in my printout when I use duplex printing. What should I do?

• In Windows, click Adjust Print Density and adjust the Document Type, Print Density, and Increased Ink Drying Time settings.
  
  In Macintosh, select Auto Duplex Printing Settings from the pop-up menu and adjust the Select Document Type, Print Density, and Increased Ink Drying Time settings.